[INFO] fetching crate future-utils 0.12.1...
[INFO] checking future-utils-0.12.1 against master#33fdb797f59421c7bbecaa4588ed5d7a31a9494a for pr-87190-3
[INFO] extracting crate future-utils 0.12.1 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate future-utils 0.12.1 on toolchain 33fdb797f59421c7bbecaa4588ed5d7a31a9494a
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+33fdb797f59421c7bbecaa4588ed5d7a31a9494a" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate future-utils 0.12.1
[INFO] finished tweaking crates.io crate future-utils 0.12.1
[INFO] tweaked toml for crates.io crate future-utils 0.12.1 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+33fdb797f59421c7bbecaa4588ed5d7a31a9494a" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+33fdb797f59421c7bbecaa4588ed5d7a31a9494a" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+33fdb797f59421c7bbecaa4588ed5d7a31a9494a" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8ae99575c71387b0fa9683fb5daf02165be38e248f297743a0763663c0ced42a
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "8ae99575c71387b0fa9683fb5daf02165be38e248f297743a0763663c0ced42a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8ae99575c71387b0fa9683fb5daf02165be38e248f297743a0763663c0ced42a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8ae99575c71387b0fa9683fb5daf02165be38e248f297743a0763663c0ced42a", kill_on_drop: false }`
[INFO] [stdout] 8ae99575c71387b0fa9683fb5daf02165be38e248f297743a0763663c0ced42a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+33fdb797f59421c7bbecaa4588ed5d7a31a9494a" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a29d665bf1355fdc8fb7687c3f682130f03057f957626012d9b320f2a1bc4e0c
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "a29d665bf1355fdc8fb7687c3f682130f03057f957626012d9b320f2a1bc4e0c", kill_on_drop: false }`
[INFO] [stderr]    Compiling log v0.4.14
[INFO] [stderr]     Checking void v1.0.2
[INFO] [stderr]     Checking tokio-io v0.1.13
[INFO] [stderr]     Checking mio v0.6.23
[INFO] [stderr]     Checking tokio-threadpool v0.1.18
[INFO] [stderr]     Checking log v0.3.9
[INFO] [stderr]     Checking tokio-codec v0.1.2
[INFO] [stderr]     Checking tokio-fs v0.1.7
[INFO] [stderr]     Checking tokio-reactor v0.1.12
[INFO] [stderr]     Checking mio-uds v0.6.8
[INFO] [stderr]     Checking tokio-udp v0.1.6
[INFO] [stderr]     Checking tokio-tcp v0.1.4
[INFO] [stderr]     Checking tokio-uds v0.2.7
[INFO] [stderr]     Checking tokio v0.1.22
[INFO] [stderr]     Checking future-utils v0.12.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/future_ext.rs:109:32
[INFO] [stdout]     |
[INFO] [stdout] 109 |         Self: Future<Error=Box<Any + Send + 'static>>,
[INFO] [stdout]     |                                ^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Any + Send + 'static`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout]     = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]     = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/resume_unwind.rs:21:25
[INFO] [stdout]    |
[INFO] [stdout] 21 |     F: Future<Error=Box<Any + Send + 'static>>,
[INFO] [stdout]    |                         ^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Any + Send + 'static`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:54:32
[INFO] [stdout]    |
[INFO] [stdout] 54 | pub type BoxFuture<T, E> = Box<Future<Item=T, Error=E>>;
[INFO] [stdout]    |                                ^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Future<Item=T, Error=E>`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:55:32
[INFO] [stdout]    |
[INFO] [stdout] 55 | pub type BoxStream<T, E> = Box<Stream<Item=T, Error=E>>;
[INFO] [stdout]    |                                ^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Stream<Item=T, Error=E>`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:56:30
[INFO] [stdout]    |
[INFO] [stdout] 56 | pub type BoxSink<T, E> = Box<Sink<SinkItem=T, SinkError=E>>;
[INFO] [stdout]    |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Sink<SinkItem=T, SinkError=E>`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:58:36
[INFO] [stdout]    |
[INFO] [stdout] 58 | pub type BoxSendFuture<T, E> = Box<Future<Item=T, Error=E> + Send>;
[INFO] [stdout]    |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Future<Item=T, Error=E> + Send`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:59:36
[INFO] [stdout]    |
[INFO] [stdout] 59 | pub type BoxSendStream<T, E> = Box<Stream<Item=T, Error=E> + Send>;
[INFO] [stdout]    |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Stream<Item=T, Error=E> + Send`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:60:34
[INFO] [stdout]    |
[INFO] [stdout] 60 | pub type BoxSendSink<T, E> = Box<Sink<SinkItem=T, SinkError=E> + Send>;
[INFO] [stdout]    |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Sink<SinkItem=T, SinkError=E> + Send`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:62:28
[INFO] [stdout]    |
[INFO] [stdout] 62 | pub type IoFuture<T> = Box<Future<Item=T, Error=io::Error>>;
[INFO] [stdout]    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Future<Item=T, Error=io::Error>`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:63:28
[INFO] [stdout]    |
[INFO] [stdout] 63 | pub type IoStream<T> = Box<Stream<Item=T, Error=io::Error>>;
[INFO] [stdout]    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Stream<Item=T, Error=io::Error>`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:64:26
[INFO] [stdout]    |
[INFO] [stdout] 64 | pub type IoSink<T> = Box<Sink<SinkItem=T, SinkError=io::Error>>;
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Sink<SinkItem=T, SinkError=io::Error>`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/future_ext.rs:109:32
[INFO] [stdout]     |
[INFO] [stdout] 109 |         Self: Future<Error=Box<Any + Send + 'static>>,
[INFO] [stdout]     |                                ^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Any + Send + 'static`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout]     = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]     = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/resume_unwind.rs:21:25
[INFO] [stdout]    |
[INFO] [stdout] 21 |     F: Future<Error=Box<Any + Send + 'static>>,
[INFO] [stdout]    |                         ^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Any + Send + 'static`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:54:32
[INFO] [stdout]    |
[INFO] [stdout] 54 | pub type BoxFuture<T, E> = Box<Future<Item=T, Error=E>>;
[INFO] [stdout]    |                                ^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Future<Item=T, Error=E>`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:55:32
[INFO] [stdout]    |
[INFO] [stdout] 55 | pub type BoxStream<T, E> = Box<Stream<Item=T, Error=E>>;
[INFO] [stdout]    |                                ^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Stream<Item=T, Error=E>`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:56:30
[INFO] [stdout]    |
[INFO] [stdout] 56 | pub type BoxSink<T, E> = Box<Sink<SinkItem=T, SinkError=E>>;
[INFO] [stdout]    |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Sink<SinkItem=T, SinkError=E>`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:58:36
[INFO] [stdout]    |
[INFO] [stdout] 58 | pub type BoxSendFuture<T, E> = Box<Future<Item=T, Error=E> + Send>;
[INFO] [stdout]    |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Future<Item=T, Error=E> + Send`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:59:36
[INFO] [stdout]    |
[INFO] [stdout] 59 | pub type BoxSendStream<T, E> = Box<Stream<Item=T, Error=E> + Send>;
[INFO] [stdout]    |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Stream<Item=T, Error=E> + Send`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:60:34
[INFO] [stdout]    |
[INFO] [stdout] 60 | pub type BoxSendSink<T, E> = Box<Sink<SinkItem=T, SinkError=E> + Send>;
[INFO] [stdout]    |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Sink<SinkItem=T, SinkError=E> + Send`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:62:28
[INFO] [stdout]    |
[INFO] [stdout] 62 | pub type IoFuture<T> = Box<Future<Item=T, Error=io::Error>>;
[INFO] [stdout]    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Future<Item=T, Error=io::Error>`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:63:28
[INFO] [stdout]    |
[INFO] [stdout] 63 | pub type IoStream<T> = Box<Stream<Item=T, Error=io::Error>>;
[INFO] [stdout]    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Stream<Item=T, Error=io::Error>`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:64:26
[INFO] [stdout]    |
[INFO] [stdout] 64 | pub type IoSink<T> = Box<Sink<SinkItem=T, SinkError=io::Error>>;
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Sink<SinkItem=T, SinkError=io::Error>`
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 11 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 11 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 5.75s
[INFO] running `Command { std: "docker" "inspect" "a29d665bf1355fdc8fb7687c3f682130f03057f957626012d9b320f2a1bc4e0c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a29d665bf1355fdc8fb7687c3f682130f03057f957626012d9b320f2a1bc4e0c", kill_on_drop: false }`
[INFO] [stdout] a29d665bf1355fdc8fb7687c3f682130f03057f957626012d9b320f2a1bc4e0c